The first time I used my heating system last fall, I noticed a strange odor which I initially attributed to chemicals used to clean the engine. This was required after a service tech failed to reinstall the oil reservoir cap after an oil change, resulting inthe entire engine compartment beingsprayed with oil.Afterwards, the odor seemed more like mold or mildew than chemicals, and at that point I wondered if something had gotten wet when the garage cleaned the engine compartment. Now, I'm wondering if it was just coincidence that I used the heating system for the first time this season immediately after the unfortunate oil change incident.

The smell is intermittent. Strangely, I notice a particularly strong whiff immediately after taking a sharp corner, braking suddenly, driving down a steep hill, etc. Any ideas if the odor might have been caused by something getting wet during the engine shampoo? Or,has my vehicle just reached an age when something could be "growing" in the heating system. It's a 2004 Mazda 3 Sport.

How should I try to get rid of the odor? Is it something I could do myself, or should I be taking it to a specialized dealer? Other than the smell, the car is immaculate inside, so I'm sure there's nothing rotting under a seat or floor mat, etc.